When The method is a forecasting method based on the idea that the weather on any date will be close to the average of the weather that occurred on that date throughout the years.?

The method you are referring to is known as "climatology" forecasting. It relies on historical weather data to predict future weather conditions by averaging past weather observations for a specific date. This approach assumes that weather patterns tend to recur on the same date over time, providing a baseline for forecasts. While useful for long-term predictions, it may not account for short-term variations or extreme weather events.